1. Field of the Invention
This invention relates to a dry gas meter of the kind in which flexible diaphragms work back-and-forth in chambers to which the gas being metered is alternately admitted and exhausted. Such meters will be termed hereinafter "meters of the kind described".
2. Discussion of the Prior Act
Conventionally meters have had their working parts located in an external casing. For example DE-A-1473042 shows upper and lower external casing parts secured together by flanges adjacent the midheight of the meter and enclosing all the meter parts. Similarly DE-A-2756163 shows meter parts which are intended to be included in an external casing. DE-C-733288 shows a simple meter which may have no external casing but does not have a unitary core defining first, second and third chambers in accordance with those of the present invention.
FR-A-1466742, which is regarded as the closest prior art, comprises a unitary core defining first, second and third chambers. However, it is not clear that this meter is not intended to have an outer casing and there is no fourth lower chamber and lower cover member.
It is desired that meters of the kind described be made smaller, neater and of simpler construction without loss of strength of durability.